lavfi/hue: add process_command callback

This allows dynamic reconfiguration of the filter.
The callback uses some code that was in the init function. Hence this code
has been moved in its own function.

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 4824d9c2e6..2312d77517 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2350,6 +2350,18 @@ hue=PI/2:1
 @end example
 @end itemize
 
+@subsection Commands
+
+This filter supports the following command:
+@table @option
+@item reinit
+Modify the hue and/or the saturation of the input video.
+The command accepts the same named options and syntax than when calling the
+filter from the command-line.
+
+If a parameter is omitted, it is kept at its current value.
+@end table
+
 @section idet
 
 Interlaceing detect filter. This filter tries to detect if the input is